Hi all

Yesterday on the way to work (10 miles each way) after about 8 miles the engine seemed to miss a beat, but then carried on a further 2 miles before as I pulled off a roundabout the engine completly stopped. The oil light then came on, the temperature guage continued to read normal.

The engine would not restart, I left the car for a couple of hours and it started. I topped up oil (It was a little low) and it ran perfectly all the way home.

Today travelling to work around the same place it again missed a beat, this time the heater plug light flashed on, and the temperature guage then started to float between 0 and a quarter of it's normal range. The water level hasn't changed throughout, there is no water in the oil. plenty of heat comes through when the heater is set to heat the car.

Does this sound like one problem or a couple at the same time? I suspect the thermostat has now gone what do you think?

Please help.

Ben

Replacing the coolant temp sensor is where I would start. Erratic temp gauge is normally the first sign that the CTS is dying. Plays hell with the ECU.

Edited 9 August, 201015 yr by pauldazzle

Replacing the coolant temp sensor is where I would start. Erratic temp gauge is normally the first sign that the CTS is dying. Plays hell with the ECU.

Where is the coolent sensor? is it attched to the plastic bit the top hose connects to on the engine? Sorry for being daft but what does CTS stand for?

One final question what should the parts cost me?

Sorry for being daft but what does CTS stand for?

Coolant Temperature Sensor

Not expensive about 30 quid I think

Coolant Temperature Sensor

Not expensive about 30 quid I think

It's obvious now.

Now I feel a fool.

I have just changed the oil (I was going to do it anyway) and went for a spin to see how it ran.

It ran perfectly for about 8 miles then again the engine cut out and the oil light came on. The temperature gauge worked as normal during this run.

This is what I think,

Either there is a fault with the the oil pressure switch or the oil pressure valve is stuck, triggering the ECU to shut down the engine when excessive pressure is reached.

Only when the oil pressure has dissapated (after about 10 minutes) can I continue. The erratic temperature gauge after a shutdown is a red herring.

Let me know what you think, either way I am going to take to my local garage tomorrow afternoon.

Could the oil pickup filter be blocked?

At the point when it all goes wrong, have you been taking any corners / strange angles in the road / up/down of the road surface?

Edited 9 August, 201015 yr by mbames

Could the oil pickup filter be blocked?

At the point when it all goes wrong, have you been taking any corners / strange angles in the road / up/down of the road surface?

I guess this could be possible, is the oil pickup the usual pipe with a fine mesh on the octavia?

The first time it happened was after pulling of a roundabout, the last time was 100 yards after a small bend. Which fits with what you are asking, however if I go round any tight bends early in the run it has no effect.

I believe that is what the oil pick up is like on the octy, although I have never had the sump off on a TDI to have a look.

Well took it to the garage tonight and it only covered about 3 miles before cutting out. So I had to be towed the rest of the way. I should find out tomorrow what could be wrong.

Someone was telling me today they knew someone who had a VW where the imoboliser kept cutting in and killing the engine at random times, could my problem be down to somthing like this?

X relay fault, I'd guess. Do a search for relay 109 and you'll know more. Basically when it fails the engine will stop and there will not be any relevant fault codes stored. A new relay is around £20 and about 15 minutes to fit.

X relay fault, I'd guess. Do a search for relay 109 and you'll know more. Basically when it fails the engine will stop and there will not be any relevant fault codes stored. A new relay is around £20 and about 15 minutes to fit.

You were spot on, I got the car back today and relay 109 was the fault. A huge releif it was nothing else more serious.

Thanks for the advise, you know your stuff.